1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to an antenna. More particularly, the present invention relates to an antenna and a method for controlling its radiation direction by adjusting counter regions of radiators.
2. Description of the Related Art
Antennas convert electrical signals into electromagnetic waves and radiate them into a free space, and vice versa. In general, an effective region where the antenna can radiate or detect the electromagnetic waves is called a radiation pattern, and a direction of the radiation pattern is called a radiation direction.
In the mean time, antennas aimed at short range communications or military purposes can be implemented to have a sharp radiation pattern to increase antenna reception efficiency. To this end, a plurality of antennas is arranged in a specific structure to match the radiation pattern and the radiation power of the antennas. As a result, the overall radiation pattern can be sharpened and the electromagnetic waves of the antennas can be radiated much further. Such an antenna structure is called an array antenna. The array antenna can attain the sharp radiation pattern.
When the radiation pattern is sharp, it is difficult to receive omni-directional signals. Thus, as for the sharp radiation pattern, it is preferred to receive signals in various directions by adjusting the radiation direction.
The array antenna can steer the direction of the radiated beam by regulating a phase of the signals transmitted on the antennas. However, since the array antenna utilizes the multiple antennas, its size is quite large.
Therefore, what is needed is a method for adjusting the radiation direction in various directions without employing the array antenna.